// @dart = 2.9
library test;

abstract class I1 {
  void f(int i);
}

abstract class I2 {
  void f(Object o);
}

abstract class C implements I1, I2 {}

class D extends C {
  void f(Object o) {}
}

abstract class E implements I2, I1 {}

class F extends E {
  void f(Object o) {}
}

void g1(C c) {}
void g2(E e) {}
main() {}